Disconnection of the organic moiety in chromium and tungsten complexes [(dithiin)M(CO)5]

ALEJANDRO M. GRANADOS, ALEJANDRO M. FRACAROLI,JERONIMO KREIKER, RITA HOYOS DE ROSSI

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY

Año: 2006 vol. 19 p. 823 - 828

0894-3230

ABSTRACT: The reaction of 5-alkylthio-3H-1,2-dithiole-3-thione derivatives with Fischer alkoxy carbenes gives 1,3-dithiin dithioorthoesters derivatives complexed with M(CO)5 (M¼Cr or W).We report here that the dithiin derivativefree of metal can be obtained by ligand exchange using acetonitrile, methanol, phenyl methyl sulfide or (Ph)3P. Methanol gives the best results from a preparative point of view. The reaction with acetonitrile was shown to be reversible and the kinetic of ligand exchange and the activation parameters were determined. From these data it is concluded that the mechanism is predominantly dissociative forM¼Cr and it has some contribution of the associative mechanism for M¼W. Copyright # 2007 John Wiley & Sons, Ltd.H-1,2-dithiole-3-thione derivatives with Fischer alkoxy carbenes gives 1,3-dithiin dithioorthoesters derivatives complexed with M(CO)5 (M¼Cr or W).We report here that the dithiin derivativefree of metal can be obtained by ligand exchange using acetonitrile, methanol, phenyl methyl sulfide or (Ph)3P. Methanol gives the best results from a preparative point of view. The reaction with acetonitrile was shown to be reversible and the kinetic of ligand exchange and the activation parameters were determined. From these data it is concluded that the mechanism is predominantly dissociative forM¼Cr and it has some contribution of the associative mechanism for M¼W. Copyright # 2007 John Wiley & Sons, Ltd.